The invention relates to the field of construction tools. More particularly, the invention relates to the field of building construction tools utilized in measuring or adjusting the slope of a surface.
In the field of building construction, some surfaces such as floors or other elements such as moldings are typically required to be horizontal with respect to level ground. Similarly, some surfaces such as walls or other elements such as vent pipes or chimneys are typically required to be vertical or perpendicular with respect to level ground. Still other surfaces such as sloped roofs and porch flooring or other elements such as pipes may be required to be constructed at some acute angle to the horizontal. For instance, waste water drain pipes may be required by building codes to be installed at a slope of ⅛ inch per foot, ¼ inch per foot, or ½ inch per foot depending on particular applications. These slopes correspond to approximate angles from the horizontal of 0.60 degrees, 1.2 degrees, and 2.4 degrees, respectively.
Since at least the 1930s, those in the construction industry have had a tool to aid in the construction of horizontal and vertical surfaces. A “spirit” or “bubble” level is an instrument that typically includes a slightly curved or cylindrical glass tube which is filled with a liquid, such as an alcohol. In addition to the liquid, a small air void is enclosed within the glass tube. At even the slightest inclination off of the horizontal, relative to level ground, the bubble will travel away from the center of the tube as an indication that the surface is not level. The tube typically is fixed within an elongate member and may either be fixed parallel to the length of the elongate member or perpendicular to the length of the elongate member. In use, the elongate member is to be held against the surface to be measured. If one in the construction industry wishes to check to see if a construction surface is vertical and, thereby perpendicular to the horizontal, he will utilize a spirit level having the tube perpendicular to the length of the elongate member. Likewise, if he wishes to check to see if a construction surface is horizontal, he will utilize a spirit level having the tube parallel to the length of the elongate member.
Despite having such ready-made tools for measuring horizontal and vertical surfaces for at least 70 years, those engaged in the field of building construction have limited options for readily, easily, and accurately measuring and adjusting the slope of surfaces that are between horizontal and vertical, that is, those angles that are acute to the horizontal. This need is especially apparent for those slopes of slight angle, where accuracy is important, such as necessary for waste water gravity sewage drains. In order to measure such angles, those in the industry must use time-consuming methods such as physically measuring the rise (or fall) and run with an instrument designed for length measurement such as a tape measure. Those in the industry may use complicated, often inaccurate, devices requiring many adjustments by the use. Or, as is often the case, those in the industry simply “eyeball” the slope as a form of guess or estimation without physically measuring the slope. Such estimations can lead to considerable construction defects which can be costly to repair. Such estimations can lead to inefficiencies that are outside of design parameters. Thus, for many years there has been a long felt and unsatisfied need in the art for a device that can permit those in the construction industry to quickly and easily ascertain the angle of slope of a surface to ensure it is in conformity with applicable building codes, design guidelines, blueprints, preferred practices and the like, particularly as it relates to a slope of slight inclination.